From owner-freebsd-hackers@freebsd.org Sat Jul 25 15:33:49 2015 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 0C27F9AAC68 for ; Sat, 25 Jul 2015 15:33:49 +0000 (UTC) (envelope-from deco33000@yandex.com) Received: from forward11h.cmail.yandex.net (forward11h.cmail.yandex.net [IPv6:2a02:6b8:0:f35::9c]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "forwards.mail.yandex.net", Issuer "Certum Level IV CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id BB0D511E7 for ; Sat, 25 Jul 2015 15:33:48 +0000 (UTC) (envelope-from deco33000@yandex.com) Received: from web20h.yandex.ru (web20h.yandex.ru [84.201.186.49]) by forward11h.cmail.yandex.net (Yandex) with ESMTP id 1DF36218D9 for ; Sat, 25 Jul 2015 18:33:35 +0300 (MSK) Received: from 127.0.0.1 (localhost [127.0.0.1]) by web20h.yandex.ru (Yandex) with ESMTP id B841013213B3; Sat, 25 Jul 2015 18:33:34 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.com; s=mail; t=1437838414; bh=E/qmBoC5o5ZOUNIkstrJe3Vf3tzW0MGTVBelqaRpctY=; h=From:To:In-Reply-To:References:Subject:Date; b=jRTX+m7v7ZZ3rat1IignWHw3RUI+q0A7paQozeug4t1H0HM9Itq510KAoOjXduqNl o0Ay8J/HWPssu4qvrGMB/XZ27JRET8h0Y9awFw1fAw6Z416PeYpeLp7uGwWmx7nY4F Ltvzy2qXb95IHafJBDUiGlm6t7jBeO3K2B8IcCrU= Received: by web20h.yandex.ru with HTTP; Sat, 25 Jul 2015 18:33:33 +0300 From: deco33000@yandex.com To: "freebsd-hackers@freebsd.org" In-Reply-To: <1226791437830729@web8g.yandex.ru> References: <1226791437830729@web8g.yandex.ru> Subject: Re: Timekeeping between two hardclocks MIME-Version: 1.0 Message-Id: <1408761437838413@web20h.yandex.ru> X-Mailer: Yamail [ http://yandex.ru ] 5.0 Date: Sat, 25 Jul 2015 17:33:33 +0200 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=koi8-r X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 25 Jul 2015 15:33:49 -0000 huumm.. Did I get it wrong ? we cannot guess where we are in time, we just cache the hardware clock and do some calculations on it up to the next hardware read. That way, we don't need to ask the hardware all the time. I was wrong, thinking that we could derivate the current timestamp (the exact one, at the request moment) without ever needing hardware. That would have been genius. But we just cache it. Simple. Is my understanding right now ? --š Jog